The embodiments disclose a method in a base station for extracting a resource block at a frequency band from a signal received from a terminal device in a radio communication system employing OFDM. The method comprising: removing a CP portion corresponding to the resource block from the signal; for each of a predetermined number of successive symbols in the signal after the CP portion corresponding to the resource block has been removed, performing a FFT of the symbol, extracting a frequency domain signal corresponding to the frequency band from the FFT of the symbol, performing an IFFT on the extracted frequency domain signal to yield a time domain signal, and storing the time domain signal to form a time sequence by concatenation; performing a FFT of the stored time sequence; and extracting subcarriers corresponding to the resource block from the FFT of the stored time sequence.

In accordance with an embodiment of the present invention, a method for receiving a signal, comprising the estimation step for estimating time and frequency shifts that are embedded in the received signal, to cancel-out shifts, wherein the method refers to the non-commutative shift parameter space of co-dimension 2.

Embodiments of the present disclosure relate to a data transmission method and a communications device. The method includes: performing an interpolation operation on a first signal sequence to obtain a second signal sequence, where a length of the second signal sequence is greater than a length of the first signal sequence; mapping the second signal sequence onto a subcarrier to obtain a second signal sequence that is on the subcarrier; performing an inverse fast Fourier transform (IFFT) on the second signal sequence that is on the subcarrier, to obtain a time-domain signal, and transmitting the time-domain signal. According to the embodiments of the present disclosure, a delay deviation can be better resisted.

This disclosure provides methods, apparatuses, wireless nodes, and computer-readable mediums for wireless communications. In one aspect, a method is provide for a Barker-modulated waveform with constant envelope for a wireless local area network (WLAN) signal. A method that may be performed by a transmitter device includes generating a Barker-modulated signal having a constant envelope and transmitting the Barker-modulated signal in a WLAN.

A method and an apparatus for determining a time offset are disclosed. The method includes: obtaining, by a device at a head end, a time-domain signal based on a received signal; and then determining a time offset based on values of peak-to-average ratios of a preset quantity of symbols starting from a q.sup.th symbol in the time-domain signal, where a peak-to-average ratio of the q.sup.th symbol is greater than a preset threshold. A new method for determining a time offset is provided, and takes advantages that the time-domain signal obtained by the device at the head end has stronger capabilities of resisting interference such as frequency offset and phase noise. The method for determining a time offset can be applied both to initial ranging and periodic ranging.

In accordance with an embodiment of the present invention, a method for receiving a signal, comprising the estimation step for estimating time and frequency shifts that are embedded in the received signal, to cancel-out shifts, wherein the method refers to the non-commutative shift parameter space of co-dimension 2.

In accordance with an embodiment of the present invention, a method for receiving a signal, comprising the estimation step for estimating time and frequency shifts that are embedded in the received signal, to cancel-out shifts, wherein the method refers to the non-commutative shift parameter space of co-dimension 2.

Disclosed methods of terrestrial station monitoring of downlink signal quality include receiving a sequence of samples of reference symbol slots of a downlink burst, and estimating a time offset between a local clock and a timing of a symbol pattern carried by the reference symbol slots, using a local copy of the reference symbol pattern. A corresponding time correction is applied to the sequence of samples to form time corrected samples of symbols carried by the reference symbol slots. A frequency offset between the time corrected samples of the symbols carried by the reference symbol slots and a local clock is estimated. A corresponding frequency compensation is applied to the time corrected samples, forming time/frequency compensated samples of the symbols carried by the reference symbol slots. A signal to noise plus interference ratio (SNIR) estimation data, and corresponding estimate of signal path, is generated, based on moments of the time/frequency compensated samples.

Processing of a data packet within a received wireless signal includes determining a frequency modulation (FM) domain carrier frequency offset (CFO) estimate component from a plurality of samples of the received wireless signal, determining a phase domain CFO estimate component from the plurality of samples of the received wireless signal, and determining a CFO estimation as a function of the FM domain CFO estimate component and the phase domain CFO estimate component. The data packet may be a Bluetooth Low Energy data packet. The FM domain CFO estimate component and the phase domain CFO estimate component may be determined from samples of a preamble field of the data packet.

Disclosed methods of terrestrial station monitoring of downlink signal quality include receiving a sequence of samples of reference symbol slots of a downlink burst, and estimating a time offset between a local clock and a timing of a symbol pattern carried by the reference symbol slots, using a local copy of the reference symbol pattern. A corresponding time correction is applied to the sequence of samples to form time corrected samples of symbols carried by the reference symbol slots. A frequency offset between the time corrected samples of the symbols carried by the reference symbol slots and a local clock is estimated. A corresponding frequency compensation is applied to the time corrected samples, forming time/frequency compensated samples of the symbols carried by the reference symbol slots. A signal to noise plus interference ratio (SNIR) estimation data, and corresponding estimate of signal path, is generated, based on moments of the time/frequency compensated samples.